High energy beam current welding press welding process and special clamp

Abstract

The invention discloses a TiNi shape memory alloy melting and connecting technology, in particular to a high-energy beam welding press welding technology and a specific clamp. The invention adopts a high-energy density beam flow as a welding implementing heat source with the advantages of centralized and straight voltaic arc energy and high voltaic arc penetration factor, thus shortening the whole connecting time, decreasing the heating surface area and reducing heat input to the most extent, eliminating the heat effect area and effectively improving the crassitude problem of the welding line structure. The specific tooling and fixture adopted by the invention can squeeze the melt welding line metal out completely by utilizing a pretightening force when an alloy wire joint part is melt, thus keeping the crystal grains of the welding joint to be approach to a parent metal and no generation of new phases, the welding line welded with a joint to be plump and a smooth transition to acquire a joint basically formed by uniform parent metal and ensuring the tensile-strength and memory function of the material after being welded; the invention has the advantages of simple technology, reasonable design on the clamp and convenient use. The invention can be widely used in a TiNi shape memory alloy melting and connecting technology.

Description

a technical field [0001] The invention relates to a TiNi shape memory alloy melting connection technology, in particular to a high-energy beam fusion pressure welding technology and a special fixture. Two background technology [0002] At present, the methods for connecting TiNi shape memory alloys at home and abroad include fusion welding, solid phase welding and brazing. The fusion welding of TiNi shape memory alloy includes laser welding, electron beam welding, argon arc welding, and argon arc pressure welding. These welding methods of fusion welding can usually achieve good joint formation, but its disadvantage is that it is easy to produce columnar grains in the weld, and there are oxide inclusions on the grain boundaries, etc., resulting in the tensile strength of the welded joint being lower than that of the base metal. In addition, the memory effect loss rate of welded joints is also relatively large. These two points are always difficult problems for fusion welding...

AI Technical Summary

Problems solved by technology

The shortcomings of this method are: firstly, its TIG arc heat source is not concentrated enough, so that there is a heat-affected zone in the welded joint, and the structure of the heat-affected zone is thicker than that of the base metal; secondly, the clamp it relies on can only shorten the welding wire by 1mm, and at the same time With the help of a certain upsetting force to make the molten weld structure dense, it cannot solve the problem of coarser grains and harmful new phase changes in this part of the weld structure compared with the base metal

Moreover, as the temperature changes, the shape memory effect at the joint is also different from that of the original base metal, and the coarse weld structure and heat-affected zone seriously lose the strength of the welded joint.

Images